Moving average low-pass filtering device and method

ABSTRACT

Differing from the fact that the amount of register units and adder units arranged in conventional moving average filter must be increased for processing more number of reference input signals, the present invention particularly discloses a moving average low-pass filtering device. The moving average low-pass filtering device comprises a register unit and a filtering and processing unit, and is able to use identical circuit architecture to successfully treat reference input signals with a filtering process even if the number of the reference input signals is alternatively increased. Moreover, after finishing a verification experiment by a simulator, simulation results have proved that, this novel moving average low-pass filtering device still can use identical circuit architecture to complete the filtering process under nearly the same calculation efficiency even though the number of the reference input signals is alternatively increased.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates to the technology field of electroniccircuits, and more particularly to a moving average low-pass filteringdevice and a moving average low-pass filtering method capable ofutilizing identical circuit architecture to successfully treatingreference input signals with a filtering process even if the number ofthe reference input signals is alternatively increased.

2. Description of the Prior Art

Low-pass filter is a filter capable of passing signals with a frequencylower than a cut-off frequency and attenuating signals with frequencieshigher than the cut-off frequency. In addition, low-pass filter issometimes called high-cut filter or treble-cut filter when beingimplemented in an audio circuit.

Moving average filter, one type of low-pass filter, is configured tofilter out high-frequency noises from input signals so as to smooth theinput signals. Moving average filters are widely applied in varioustechnology fields nowadays, such as wearable electronic devices, IoT andbiomedical devices. FIG. 1 shows a circuit framework diagram of aconventional moving average filter. The conventional moving averagefilter 1′ comprises a plurality of register units 11′, a plurality ofadder units 12′ and a shifter unit 13′. It is worth noting that, themoving average filter 1′ can be implemented in an application circuitfor processing 16 input signals because the amount of the register units11′ and the adder unit 12′ is respectively sixteen and fifteen.

Electronic engineers skilled in development and manufacture of themoving average filter 1′ should know that, the amount of the registerunits 11′ and the adder unit 12′ arranged in the moving average filter1′ is determined based on the number of reference input signalstemporarily stored in the register units 11′. Therefore, it isunderstood that the hardware amount and whole cost of the moving averagefilter 1′ grow with the increase of the number of the reference inputsignals.

From above descriptions, it is clear that the conventional approach forplanning and arranging related hardware units to constitute the movingaverage filter 1′ is inflexible and not very intelligent. Therefore, howto find an ideal approach for effectively solving the problem onhardware designs of the conventional moving average filter 1′ has becomethe most important study issue. In view of that, inventors of thepresent application have made great efforts to make inventive researchthereon and eventually provided a moving average low-pass filteringdevice and a moving average low-pass filtering method.

SUMMARY OF THE INVENTION

In view of the fact that the number of register units and adder unitsarranged in conventional moving average filter must be increased forprocessing more number of reference input signals, the primary objectiveof the present invention is to provide a moving average low-passfiltering device and a moving average low-pass filtering method, whereinthe moving average low-pass filtering device is able to successfullytreat reference input signals with a filtering process even if thenumber of the reference input signals is alternatively increased,without being added any additional register units and adder units intothe circuit architecture thereof. Moreover, after finishing averification experiment by a simulator, simulation results have provedthat, this novel moving average low-pass filtering device still can useidentical circuit architecture to complete the filtering process undernearly the same calculation efficiency even though the number of thereference input signals is alternatively increased. Therefore, it iseasy to know that this novel moving average low-pass filtering deviceshows a variety of advantages, including: (1) being capable ofsuccessfully treating reference input signals with a filtering processeven if the number of the reference input signals is increased, and (2)being able to use identical circuit architecture to complete thefiltering process.

In order to achieve the primary objective of the present invention, theinventor of the present invention provides an embodiment for the movingaverage low-pass filtering device, which is electrically connectedbetween a signal providing device and an electronic device, and used forreceiving successive input signals from the signal providing device andsubsequently apply a filtering process to the successive input signals,so as to correspondingly output successive signals to the electronicdevice; moreover, the embodiment of the moving average low-passfiltering device comprises:

-   a register unit for temporarily storing the successive input    signals; and-   a filtering and processing unit, being configured to access the    successive input signals from the register unit so as to    subsequently apply at least one shift process, at least one    subtracting process, and at least one adding process to the    successive input signals.

Moreover, for achieving the primary objective of the present invention,the inventor of the present invention further provides an embodiment forthe moving average low-pass filtering method, which is implemented in anexecution device, wherein the execution device is electrically connectedbetween a signal providing device and an electronic device, and used forreceiving successive input signals from the signal providing device andsubsequently apply a filtering process to the successive input signals,so as to correspondingly output successive signals to the electronicdevice; moreover, the embodiment of the moving average low-passfiltering method comprises following steps:

-   (1) providing a register unit and a filtering and processing unit in    the execution device;-   (2) letting the register unit receive successive input signals from    a memory, a storing device or the signal providing device; and-   (3) using the filtering and processing unit to access the successive    input signals from the register unit, so as to subsequently apply at    least one shift process, at least one subtracting process, and at    least one adding process to the successive input signals.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention as well as a preferred mode of use and advantages thereofwill be best understood by referring to the following detaileddescription of an illustrative embodiment in conjunction with theaccompanying drawings, wherein:

FIG. 1 shows a circuit framework diagram of a conventional movingaverage filter;

FIG. 2 shows a circuit framework diagram of a moving average low-passfiltering device according to the present invention;

FIG. 3 shows a flow chart of a moving average low-pass filtering methodaccording to the present invention; and

FIG. 4 shows a flow chart for describing detail steps of step (3).

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

To more clearly describe a moving average low-pass filtering device anda moving average low-pass filtering method according to the presentinvention, embodiments of the present invention will be described indetail with reference to the attached drawings hereinafter.

With reference to FIG. 2, which illustrate a circuit framework diagramof a moving average low-pass filtering device according to the presentinvention. As FIG. 2 shows, the moving average low-pass filtering device1 is electrically connected between a signal providing device 2 and anelectronic device 3, and used for receiving successive input signalsfrom the signal providing device 2 and subsequently apply a filteringprocess to the successive input signals, so as to correspondingly outputsuccessive signals to the electronic device 3. It needs to furtherexplain that the said signal providing device 2 can be an A/D converter,a sensor, a receiver, a voice recognition device, a memory, a storingdevice, or digital a signal outputting device. On the other hand, theelectronic device 3 can be a dynamic random access memory (DRAM), auniversal serial bus (USB), a wired transmission device, a wirelesstransmission device, or a data storing device.

From FIG. 2, it is found that the moving average low-pass filteringdevice 1 of the present invention merely comprises a register unit 11and a filtering and processing unit 12, wherein the register unit 11 isused for temporarily storing successive input signals outputted by thesignal providing device 2. Moreover, the filtering and processing unit12 is configured to access the successive input signals from theregister unit 11 so as to subsequently apply at least one shift process,at least one subtracting process, and at least one adding process to thesuccessive input signals.

In the present invention, the register unit 11 is constituted by a firstregister 111 and a second register 112. It is worth explaining that,after the filtering and processing unit 12 applies a moving averageprocess to one specific input signal of the successive input signalsstored in the first register 111, the second register 112 wouldsubsequently store the specific input signal as another one inputsignal. Therefore, according to a system clock signal, the input signalstored in the second register 112 and the input signal stored in thefirst register 111 are respectively regarded as an (N−1)-th input signalbeen treated with the moving average process and an N-th input signal.

Please refer to FIG. 2 again. The filtering and processing unit 12comprises an adder 121, a first shifter 122, a second shifter 123, and asubtractor 124. When the filtering and processing unit 12 normallyworks, the N-th input signal of the successive input signals would betreated with an adding process by the adder 12 electrically connected tothe first register 111 and the subtractor 124. Subsequently, the firstshifter 122 electrically connected to the adder 122 applies a firstshift process to the N-th input signal been treated with the addingprocess, and then the second register 112 stores the N-th input signalbeen treated with first shift process as one (N−1)-the input signal.

After finishing the adding process, the second shifter continuouslyapplies a second shift process to the (N−1)-the input signal stored inthe second register 112. Furthermore, since the subtractor 124 iselectrically connected to the second shifter 123 and the second register112, the subtractor 124 is configured to apply a subtracting process tothe (N−1)-the input signal been treated with the second shift processand the (N−1)-the input signal. Consequently, the adder 121 applies theadding process to an output signal of the subtractor 124 and the N-thinput signal.

In is worthy particularly introducing that, the technology features ofthis moving average low-pass filtering device 1 for carrying out movingaverage filtering process include: (1) to amplify a previous inputsignal (i.e., the (N−1)-th input signal) stored in the second register112 by 2^(n) times through using the second shifter 123 to leftwardshifting decimal (binary) data of the (N−1)-th input signal by n bitsbased on system clock signal; and (2) applying a subtracting process tothe (N−1)-th input signal been amplified by 2^(n) times and the (N−1)-thinput signal by using the subtractor 124, so as to obtain one (N−1)-thinput signal been amplified by 2^(n-1) times. Thus, a digital signal canbe produced by adding the (N−1)-th input signal been amplified by2^(n-1) times and the N-th input signal, wherein the said digital signalis approximately equal to the superposition of first input signal,second input signal, 3^(rd) input signal, . . . , and (2^(n))-th inputsignal. Eventually, the N-th input signal been treated with the movingaverage process can be obtained through using the first shifter 122 torightward shift decimal (binary) data of the digital signal outputtedfrom the adder 122 (i.e., the N-th input signal) by n bits.

Compared to the conventional moving average filter 1′ shown in FIG. 1,the moving average low-pass filtering device 1 proposed by the presentinvention exhibits a primary advantage of being able to use identicalcircuit architecture to successfully treat successive input signals witha moving average filtering process even if the number of the inputsignals is alternatively increased. Moreover, in order to prove thepracticability of the proposed moving average low-pass filtering device1, simulator is adopted for carrying out at least one verificationexperiment. Related experimental data are integrated in following Table(1) and Table (2).

TABLE (1) Number of input signals 2 4 8 16 32 64 Amount of 1 3 7 15 3163 adders and subtractors Amount of 1 1 1 1 1 1 shifters Amount of 3 5 917 33 65 registers Calculation 4.96 5 5 5.47 6.28 7.08 time (ns)

TABLE (2) Number of input signals 2 4 8 16 32 64 Amount of 2 2 2 2 2 2adders and subtractors Amount of 2 2 2 2 2 2 shifters Amount of 2 2 2 22 2 registers Calculation 4.99 5 5 5 5 5 time (ns)

From Table (1) and FIG. 1, it is found that the amount the amount of theregister units 11′ and the adder unit 12′ arranged in the moving averagefilter 1′ is determined based on the number of reference input signals.Thus, it is understood that, the hardware amount and whole cost of themoving average filter 1′ grow with the increase of the number of thereference input signals. However, it is worth noting that, thecalculation time of the moving average filter's does not becorrespondingly reduced with the increase of the hardware units; on thecontrary, the calculation time grows. On the other hand, Table (2) andFIG. 2 indicate that this novel moving average low-pass filtering device1 can use identical circuit architecture to apply moving averagefiltering process to successive input signals even if the number of theinput signals is alternatively increased. Moreover, experimental dataalso proved that, the moving average low-pass filtering device 1 of thepresent invention shows almost the same calculation performance whenprocessing different numbers of successive input signals.

It needs to emphasize that, although FIG. 2 indicates that the movingaverage low-pass filtering device 1 of the present invention is ahardware circuit, that does not used for limiting the implementationtype of the moving average low-pass filtering device 1. Engineersskilled in development of digital filter program should know that, thedigital filter can also be established by using mathematical algorithms,so as to be provided in an execution device like computer, processor orcontroller by a form of application program, library, variables, oroperands. Accordingly, the present invention simultaneously provides amoving average low-pass filtering method capable of being implemented inan execution device, wherein the execution device is electricallyconnected between the signal providing device 2 and the electronicdevice 3, and used for receiving successive input signals from thesignal providing device 2 and subsequently apply a filtering process tothe successive input signals, so as to correspondingly output successivesignals to the electronic device 3.

Please refer to FIG. 3, where a flow chart of the moving averagelow-pass filtering method proposed by the present invention is provided.As FIG. 3 shows, the moving average low-pass filtering method mainlycomprises 3 steps of:

-   step (S1): providing a register unit 11 and a filtering and    processing unit 12 in the execution device;-   step (S2): letting the register unit 11 receive successive input    signals from a memory, a storing device or the signal providing    device 2; and-   step (S3): using the filtering and processing unit 12 to access the    successive input signals from the register unit 11, so as to    subsequently apply at least one shift process, at least one    subtracting process, and at least one adding process to the    successive input signals.

Continuously referring to FIG. 2, and please simultaneously refer toFIG. 4, which illustrate a flow chart for describing detail steps of thestep (3). The step (3) of the moving average low-pass filtering methodcomprises following detailed steps:

-   step (S31): letting the adder 121 access the first register 111, so    as to subsequently apply the adding process to an N-th input signal    of the successive input signals;-   step (S32): using the first shifter 122 to apply the a first shift    process to the N-th input signal been treated with the adding    process;-   step (S33): using the second register 112 to temporarily store the    N-th input signal been treated with the first shift process as an    (N−1)-th input signal;-   step (S34): using the second shifter 123 to apply a second shift    process to the (N−1)-th input signal; and-   step (S35): using the subtractor 124 to apply the subtracting    process to the (N−1)-th input signal been treated with the second    shift process, wherein the adder 121 is configured to apply the    adding process to an output signal of the subtractor 124 and the    N-th input signal.

Therefore, through above descriptions, the moving average low-passfiltering device and method proposed by the present invention have beenintroduced completely and clearly; in summary, the present inventionincludes the advantages of:

(1) In view of the fact that the number of register units 11′ and adderunits 12′ arranged in conventional moving average filter 1′ (shown asFIG. 1) must be increased for processing more number of reference inputsignals, the present invention particularly provides a moving averagelow-pass filtering device 1, which is able to successfully treatreference input signals with a filtering process even if the number ofthe reference input signals is alternatively increased, without beingadded any additional register units and adder units into the circuitarchitecture thereof. Moreover, after finishing a verificationexperiment by a simulator, simulation results have proved that, thisnovel moving average low-pass filtering device still can use identicalcircuit architecture to complete the filtering process under nearly thesame calculation efficiency even though the number of the referenceinput signals is alternatively increased. Therefore, it is easy to knowthat this novel moving average low-pass filtering device shows a varietyof advantages, including: (1) being capable of successfully treatingreference input signals with a filtering process even if the number ofthe reference input signals is increased, and (2) being able to useidentical circuit architecture to complete the filtering process

(2) In addition, this moving average low-pass filtering device 1 canalso be established through using mathematical algorithms, so as to beprovided in an execution device like computer, processor or controllerby a form of application program, library, variables, or operands.

The above description is made on embodiments of the present invention.However, the embodiments are not intended to limit scope of the presentinvention, and all equivalent implementations or alterations within thespirit of the present invention still fall within the scope of thepresent invention.

What is claimed is:
 1. A moving average low-pass filtering device, beingelectrically connected between a signal providing device and anelectronic device, and used for receiving successive input signals fromthe signal providing device and subsequently apply a filtering processto the successive input signals, so as to correspondingly outputsuccessive signals to the electronic device; moreover, the movingaverage low-pass filtering device comprising: a register unit,comprising a first register for temporarily storing the successive inputsignals and a second register; and a filtering and processing unit,comprising: an adder, being coupled to the first register for applyingan adding process to an N-th input signal of the successive inputsignals; a first shifter, being coupled to the adder and the secondregister of the register unit, and being configured for applying a firstshift process to the N-th input signal that is been treated with theadding process, and the second register temporarily storing the N-thinput signal as a (N−1)-th input signal; a second shifter, being coupledto the second register of the register unit for applying a second shiftprocess to the (N−1)-th input signal; and a subtractor, beingelectrically connected to the second shifter and the second register ofthe register unit, and being configured to apply a subtracting processto the (N−1)-th input signal and the (N−1)-th input signal that is beentreated with the second shift process; wherein the adder is also coupledto the subtractor, such that an output signal of the subtractor and theN-th input signal are applied with the adding process by the adder. 2.The moving average low-pass filtering device of claim 1, wherein thesignal providing device is selected from the group consisting of A/Dconverter, sensor, receiver, voice recognition device, memory, storingdevice, and digital signal outputting device.
 3. The moving averagelow-pass filtering device of claim 1, wherein the electronic device isselected from the group consisting of dynamic random access memory(DRAM), universal serial bus (USB), wired transmission device, wirelesstransmission device, and data storing device.
 4. A moving averagelow-pass filtering method, being implemented in an execution device,wherein the execution device is electrically connected between a signalproviding device and an electronic device, and used for receivingsuccessive input signals from the signal providing device andsubsequently apply a filtering process to the successive input signals,so as to correspondingly output successive signals to the electronicdevice; moreover, the moving average low-pass filtering methodcomprising following steps: (1) providing a register unit and afiltering and processing unit in the execution device; wherein theregister unit comprises a first register and a second register, and thefiltering and processing unit comprising a first shifter, a secondshifter, and a subtractor; (2) letting the register unit receivesuccessive input signals from a memory, a storing device or the signalproviding device through the first register thereof; (31) letting theadder access the first register, so as to apply an adding process to anN-th input signal of the successive input signals; (32) using the firstshifter to apply the a first shift process to the N-th input signal thatis been treated with the adding process; (33) using the second registerto temporarily store the N-th input signal that is been treated with thefirst shift process as an (N−1)-th input signal; (34) using the secondshifter to apply a second shift process to the (N−1)-th input signal;and (35) using the subtractor to apply the subtracting process to the(N−1)-th input signal that is been treated with the second shiftprocess; wherein the adder is configured to apply the adding process toan output signal of the subtractor and the forgoing N-th input signal.5. The moving average low-pass filtering method of claim 4, wherein thesignal providing device is selected from the group consisting of A/Dconverter, sensor, receiver, voice recognition device, memory, storingdevice, and digital signal outputting device.
 6. The moving averagelow-pass filtering method of claim 4, wherein the electronic device isselected from the group consisting of dynamic random access memory(DRAM), universal serial bus (USB), wired transmission device, wirelesstransmission device, and data storing device.
 7. The moving averagelow-pass filtering method of claim 4, wherein the execution device isselected from the group consisting of computer, processor andcontroller.
 8. The moving average low-pass filtering method of claim 4,wherein both the register unit and the filtering and processing unit areprovided in the execution device by a form of application program,library, variables, or operands.
 9. The moving average low-passfiltering method of claim 4, wherein the first shift process is carriedout after rightward shifting decimal (binary) data of the N-th inputsignal that is been treated with the adding process by n bits based on asystem clock signal, and the first shift process being completed afterleftward shifting decimal (binary) data of the (N−1)-th input signal byn bits based on the system clock signal.